The present invention relates to printed plastic circuits and contacts and a method of forming them. More particularly, the subject of the invention relates to conductive coating compositions.
Conductive coatings are well-known in the art which are also known as conductive inks. Conductive inks have many favorable characteristics, in that the compositions may include metals such as silver, copper, lead or tin to provide electrical conductivity. The conductive inks also may include adhesives such as polymeric binders which provide for solderability and adhesive strength. Conductive inks have been used for many applications, including applying conductive traces to printed circuit boards. The prior art shows the application of conductive ink by silk screen printing onto a non-moldable insulating baseboard substances, such as FR4 or glass epoxy. The use of conductive inks to make printed circuit boards is an additive process which is much quicker, more easily performed and less expensive than the old subtractive process of covering FR4 completely in copper and then removing the copper except for the areas in which the traces are to remain. Such process is usually accomplished out-of-house by special manufacturers. The present invention using an additive process may be performed in-house by circuit manufacturers at great time and expense savings.
New plastics are known in the art which have characteristics, including high mechanical strength, durability, toughness, chemical resistance and high temperature performance. Liquid crystal polymers (LCPs) offer these characteristics, while providing the advantage of all moldable plastics. LCPs are able to withstand temperatures as high as 520.degree. fahrenheit before disintegrating. It is an object of the present invention to combine the high temperature and moldable properties of plastics such as LCP with the quick and convenient process of printing with conductive inks.